Mixer



May 31, 1949 A. G. GRANATH l2,471,487

MIXER I Filed Aug. 20, 1945 4 Sheets-Sheet l May 31, 1949. A. G. GRANATH- MIXER Filed Aug. 2o, 1945y 4 Sheets-Sheet 2 Ik l l III H IH..."

. Ibm

May 3l, 1949.

A. G. GRANA'rl-j MIXER 4 sheets-sheet 5 Filed Aug. 20, 1945 May 3l, 1949. A. G. GRANATH 2,471,487

- MIXER Filed Aug. 20, 1 945 4 Sheets-Sheet 4 y s@ 9a7/7 Patented May 3 1, 1949 MIXER Axel G. Granath, Chicago, Ill., assignor to Herbert S. Simpson, Evanston, Ill.

Application August 20, 1945 Serial No. 611,494

2 Claims. 1

The present invention pertains to material mixers adaptable for use in the chemical eld as well as for the treatment of materials during the treatment of which it is desirable to control the temperature of the mix.

With the advent of the present war and the tremendous increase in the requirement for products requiring the mixture of different materials in controlled atmospheres, it has become necessary to provide an improved mixer adapted for the mixture and treatment of chemical materials for the production of high explosives and the like. A mixer has also been needed that might also be adaptable for the reclaiming and reprocessing of either new or spent materials such as foundry molding sand, which usually is delivered while still in a hot condition, thereby making it desirable for the subsequent treatment of such molding material, as well as the premixture of chemical materials, to take place in an area in which the temperature of the mix may be either reduced or increased depending upon the nature of the mixture being subjected to treatment.

It is an object of this invention to provide a material mixing and treating machine of an improved and simplied type which is designed and constructed with improvements for increasing the adaptability and eiciency thereof.

It is also an object of this invention to provide an improved material mixer wherein the material being treated may be subjected to either cooling or heating treatments, depending upon the nature of the products undergoing treatment.

Still another object of the invention is the provision of an improved and simplied form of material mixer adaptable for use in the chemical eld to permit the mixing and the treatment of materials requiring the cooling of the mixture during treatment.

A further object of the invention is the provision of an improved type of material mixing and mulling machine in which the mixing crib is provided with a cooling jacket for cooling the mix during treatment in the crib, thereby making the machine adaptable for use in the production of high explosives and chemical products in which it is desirable to control the temperature of the mixtures during treatment.

It is furthermore an object of this invention to provide an improved type of material mixing and mulling machine having an improved discharge door the operation of which is positively controlled and is adapted to be held in a locked position not only when the operating medium is available, but also in the event tha/i? '0116. @0111511.11 medium 2 is turned oi or is accidentally shut olf or exhausted.

Still another object of the invention is the provision or a material mixing and mulling machine wherein the Scrapers and plow mechanism are mounted to permit the same to be accurately adjusted to a minute degree.

A feature of the invention is to provide a material mixing and mulling machine wherein the mixing crib, the turret and the wear plate are either integral or rigidly secured together to form a substantially one-piece structure and in which the wear plate forms the top of an integral cooling jacket provided in the lower portion of the crib, and through which either a cooling or a heating medium may be circulated for controlling the temperature of mixes while being treated in the crib.

An additional and further feature of the inven- 1 tion relates to the circulation of a temperature controlling liquid through a jacket forming part of a material mixing and mulling container of a machine for the treatment of chemical materials in the production of high explosives or other products during the production of which it is desirable to control the temperature of the mixture While being treated.

Other objects and features of this invention will more clearly appear from the following detailed description taken in connection with the accompanying drawings, which illustrate the embodiment of the invention.

In the drawings:

Figure 1 is a front elevational view of a mixer embodying the principles of this invention;

Figure 2 is a top plan View of the mixer with parts bro-ken away;

Figure 3 is a longitudinal vertical sectional view taken on line III- III of Figure 2 with parts shown in elevation;

Figure 4 is a transverse vertical sectional View taken on line IV-IV of Figure 2 with parts shown in elevation and with parts omitted;

Figure 5 is an enlarged detailed elevational view of the outer scraping and plowing mechanism; and

Figure 6 is an enlarged vertical elevational view of the inner mixing and plowing mechanism.

As shown in the drawings:

The present invention is particularly concerned with the method of and the apparatus for treating materials in the chemical eld for the production of products such as explosives and the like. The machine is also adapted for the conditioning of foundry sand and the reclaiming of other materials, in a manner including a temperature control of the materials being mixed and treated.

It is accordingly believed that the novel process of treating or conditioning the ingredients of a mixed product in a controlled atmosphere to either cool the mix or heat the same, depending upon the nature of the product being produced, will bestb'e understood' from a description of1 a mixing machine embodying the features of thisrv invention and by means of which the process may be practiced.

The mixing machine comprises a combinationsupporting and driving unit, a mixing unit supported thereon and a combinationdischargehopa per and door unit coacting with thel mi-xirigiunitvv and supported on the supporting unit or adjacent thereto.

The mixing machine comprises a supporting. framework I including a drive housing 2 for enclosing ai driving: uni-tv for the machine.- The drive housing 2 is provided with a bottomF 3 formed with a bearingy box iA inwhich the lower endof the- Ina-in vertical driven shaft 5' is supported( by means of a roller bearing. unit ti.v The shaft 5Y is also supported by means of a roller bearing unit 'l supported in the housing 2 as illustratedin Figure 3; Keyed or otherwise supportedion the lower portion of the vertical driven` shaft-5'i-s-a'worrn-wheel 8 disposed within-a chamber erl compartment S; Meshing with the worm wh'eel- 8' is a driving worm lil which. is rigidly secured or forms a partof a drive shaft H whichl projects outv of the drive housing 2 and has sec ured on the outer projecting end thereof a-pulley I 2- around which a driving belt i3 is engaged. 'Ifhebelt lf3 is alsov engaged around a small-pulley i 4 supported on the shaft of a driving motor I5', from which'a driveistra-nsferred to the main vertical shaft 5. The shaft 5 which is engaged in and on the casting H. The mix-ing and treating uni-t is secured in place by means of bolts i8. The mixing unit includes a container comprising a bottom or base plate i9 having integrally formed thereonor welded thereto the lower end of a cylindrical shell or crib 2li terminating at its upper errdinan integral outwardly projecting at rim or flange 2|, on which a material delivering hood or hopper, partly illustratedin dotted lines, may, irr some cases be tightly seated for the delivery of materials into the crib. Integrally formed centrally onthecrib base plate i9 is an upwardly projecting turret 22 through which the main vertical driven shaft 5 projects- Integral-ly formed around the turret 22 or rigidly secured thereto, by welding or other means@ is a combination wear plate 23 which is spaced above the crib base plate I9 and forms the .top wall ofaL temperature control jacket including the chamber 24 as clearly illustrated in Figure 3: y The outer` peripheral edge ofy the wear plate 23 is integral with the inner wall of the crib 'All or is rigidly secured thereto by welding or the like.v It will thus be noted that a mixing or treating container is provided forv the mixer, said container consisting of the crib having a temperature control jacket in the 4 lo'wer portion thereof around the turret, all of said parts being integrally formed with one another or so securely welded together that they form a unitary construction.

The portion of the main driven shaft 5 which projects outwardly through the crib turret 22 is journaled in a ball bearing unit 25 through which the upper end of the shaft 5 projects. Keyed or otherwise secured-ion theuppen'projecting end of the-` main driven shaft iabovethebearing unit 25 is a propulsion head 26. Integrally projecting from one side of the propulsion head 25 is a plow supporting arm 2l which projects radially outwardly from the propulsion head and is curved.

f The? outerend of the plow supporting arm 2'! is curedby means of screws 32 to the lower slotted end of. the supporting bar 2S is a plow bladefi;

illustrated in detail in Figure andzprovided-with' a 4scrapingedge 34 at the. inner. end thereof adapted` to move-over the exterior of the turretv 22 while the lower plow-ingv edgel of' the plow :blade 33, is positioned-1 alongztheA lowe-r` edge of the plow to. travel over the top.v ofthe wear. platev 23 wheni the propulsion head 2liV isrotated bythe shaft 5;

Integrallyform-ed on the propulsion head 26 porting arm or beam 34v which is formed with a bearing-l` sleeve 35 positioned` atrig-ht anglestothe verticalshaft 5.. The outer end of the plow beam.

34 adjustably supportsa guide arm 35: having a guide slot or groove. 3l' formed therein through which-` clamping bolts- 39? engage; The bolts 39 are'V carriedby the plow beam 34 and engage f' adjusted position with respect to-the plow beam Ii'itegrally formedA on the outer end of the guide arm 36 ls a plow head. 4u formed with a vertical guide groove.- rIhe upper end. of a plow supporting bar or post- 4l is` adjustablyy engaged in the plow head 4E!l and is held in an adjusted position therein, by means of a clamping plate 42 held in place by screw bolts 43. The lower end of the plow supporting bar 4!y is provided with slots through which clamping bolts 44 are engaged. The clamping bolts 44 are engaged through aperturesI in an` outer plow blade l5 having a lower edgey 46whfich= is adaptedto travel over the top surface of the wear plate 23. The outer plow blade 45 is also provided with a' vertical scraping edge 451, which as clearly illustrated in Figure 2, is adapted to travel over the inner face of the lower portion of the cylindrical crib 2li when the mixing-*mechanisms are in operation.

The mulling mechanism of the mixer is also associated with. the propulsion head 26 and in-` cludes a stub shaft or axle 48 which is rotatably journaled in the bearing sleeve 35. Keyed or otherwise secured on a projecting end of the axle 48 is collar 49 of a crank arm 5!) the free end of which is formed with an integral collar 5|. Integrally formed on the collar 5I of the crank arm is an elbow bracket 52, having adjustably threaded through al threaded passage therein, an adjusting screw 53 the lower projecting end of which is adapted to seat against a stop shoulder 54 (Figure 4) to provide an arrangement for limiting the downward swing of the crank arm 5G. An arrangement is thereby provided for adjusting the positioning of the mulling mechanism with respect to the wear plate 23. Secured by means of a screw bolt or other suitable means within the crank arm collar 5l is one end of a muller subshaft or axle E55 on the outer end of which is rotatably journalled a pressure roll or muller 56, which may be of any selected type and weight desired to permit the periphery of the muller to travel over materials on the wear plate 23 of the mixing crib.

It will thus be noted that the mixing and mulling mechanism within the mixing container or crib are adapted to be operated by the rotation of the propulsion head 25, which in turn is rotated by the vertical driven shaft 5 through the worm drive mechanism connected to receive a drive from the motor I5.

Attention is called to the mountings for the inner and outer plows 33 and d5 which are 'adjustably mounted so that they can be adjusted to within a very small exact degree.

One of the important features of the present mixer is the provision of a unitary mixing container which is formed with an integral temperature control jacket in the lower portion there of with the top of said jacket also serving as the wear plate for the mixing crib. The chamber Zd of the temperature control jacket is adapted to serve as a cooling medium by causing a cooling liquid, such as water or the like, to be admitted into the jacket chamber 2li through an intake or supply nipple 5l to the outer end of which a supply hose may be connected for supplying the cooling medium to the temperature control jacket.

For the purpose of causing the cooling medium to circulate circuitously through the water jacket chamber 2li beneath the wear plate 23 of the crib, the chamber 2t is provided with a plurality of radially directed baffle plates or Vanes 58 and 59. The baiiie vanes '53 have the outer ends thereof integrally secured to the peripheral wall of the jacke-t and extend inwardly to within a short distance of the turrent i2 where it projects through the water jacket. The baille plates or varies 5e extend from the turret outwardly and radially to within a short distance of the peripheral Wall of the jacket7 as illustrated in dotted lines in Figure 2. The baffle vanes 53 and 59 eX- tend from the crib bottom plate i9 to the wear plate 23 and thus bridge the distance between the wear plate and the bottom it so as to support the wear plate between its peripheral margins as shown in Figures 3 and 4. The varies 58 and 59 are staggered or alternately project radially in opposite directions within the compartment 24 of the temperature control jacket so that the water or cooling medium entering through the supply pipe 5'! will flow inwardly and around the inner end of the baffle vane 5S into the second division of the chamber and will then flow outwardly around the outer end of the next vane 59 and so on throughout the entire area of the jacket chamber until the last division is reached permitting the cooling medium to flow out through a discharge nipple li.

For the purpose of separating the opposite sides of the temperature control chamber so that the water will circulate in a circuitous path, a solid partition wall 6l is provided in the chamber 24 and extends from the turret 22 radially outwardly to a U-shaped closure wall 62 which extends around three sides of a crib door opening 63 provided in the base plate I9 (Figure 3). The opening t3 together with the adjoining passage @il formed by the U-shaped wall 62 and a portion of the lower part of the crib wall 20, forms a passage for the crib discharge closure mechanism which includes a closure member supported at a point or position remote or outside of the crib unit.

To permit discharge of the material which has been mixed and mulled or treated within the mixing compartment of the crib 20, the wear plate 23 is provided with a discharge opening 65. The discharge opening 65 in the wear plate 23 is pted to be closed by a door mechanism compr a metal door plate tt which is constructed to have a precision t with the discharge opening in the wear plate 23. Positioned against the outer or lower side of the door plate 66 is an apertured door seal pad or plate El which is constructed of a resilient compressible seal mate- The door pad 5l seats upon an apertured door supporting plate 6B. Bolts 69 engage freely through the supporting plate 68 and through the pad Si and thread into the door plate 66 to hold door plate and the pad securely fastened in position on the supporting plate 68.

Rigidly secured on the top surface of the door supporting plate are a plurality of stop studs 10 which are embedded in the compressible seal pad 6l and are shorter than the thickness of said seal so that when the door is moved into closed position, as shown in Figure 3, the seal pad may be compressed a predetermined amount before the upper ends of the stop studs contact against the door plate 56 to limit the compression of the seal pad. The seal pad is larger than the supporting plate E8 and larger than the door plate Se so that the peripheral margin of the seal pad is adapted. to engage against the bottom surface oi the Wear plate 23, within the passage 64, through which the door is adapted to move.

The door supporting plate $8 is integrally formed on the ends of a pair of U-shaped door hinge arms l. The mounting ends of the door hinge arms 'il are formed with sleeves 'l2 which are engaged on a door hinge shaft 13 and are secured to said shaft by means of set screws 14. The hinge shaft i3 is journalled in suitable bearings 'l5 which are formed on the outer sides of an upper hopper it which is in the form of a rectangular frame open a-t the bottom and at the top. The lower end of the upper hopper 'I6 is provided with an apertured flange 11 to permit upper hopper to be rigidly and tightly bolted, by means of the bolts lll, to the top ilange 19 of a lower discharge hopper Si) which is larger than the upper hopper it and projects underneath the base plate lli ci the crib unit as clearly illustrated Figure 3 to position an opening in the top portion oi the lower hopper to register with the opening t3 in the crib base plate I9.

The lower hopper Se is supported on the framework i and has the lower tapered end thereof provided with an outwardly projecting iiange il having secured on the lower side thereof, by means of screws 32, a seal ring 63 around which is formed a ccnipressible seal washer 84. The seal washer et is provide@L to form a tight seal between the discharge hopper Bil and the rim oi a receiving container (partly shown in dotted lines) which is adapted to be forced or tightly held against the seal washer @t to prevent any of the treated material from the mixing crib from 4cured on a projecting end escaping when the material is discharged. through the discharge hopper 8b when the crib door is opened after a mixing cycle has been completed inthe crib 2li.

For the purpose or opening the crib door 6o the door control' shaft 73 has keyed or otherwise sethereo a pinion or gear B having a gear segment llt' in mesh therewith. The gear segment @it is rotatably supported on a gear segment supporting shaft Sl which projects through the upper hopper 'l5 and through supporting sleeves formed on the upper hopper side walls. One end of the shait l projects loeyond one side of the upper hopper 'it to permit the gear segment t to be supported thereon in the plane ofthe gear 65. A gear guard 88 engages over and partially around the gear 85 and gear segment to protect the same. rihe gear guard is sepported on a bracket t@ which is rigidly bolted on one side ci the upper hopper l5.

The gear segment F53 which controls the opening and closing of' the crib door is operated by a toggle mechanism which in turn is operable by an air control mechanism. integrally formed on the gear segment 3B and in diametrical alignment with the centerline oi the gear segment is an integral gear` arm til. Projecting through the outer end of the gear arm Si@ isa link pin iii having pivotalily mounted on the opposite ends thereof, on opposite sides of the gear arm the uppei-ends of a pair oi toggle linksl The opposite' ends' oi the pair of spaced parallel toggle links er are pivotally engaged on a pin $53 which serves as a three-way connector. Also pivotally connected on the. link pin @i3 is one end of an ad jiustable toggle @d the other end of which is pivotaily supported on a link pin 95 which is sup ported in a pair oi spaced ears or plates @E which form an part ci a toggle supporting arm Sil, which is part` of the bracket E@ as illustrated in Eig-ure l. Aditi-stably supported on the lower portion of the toggie supporting arm` @'l' is a stop screw et against' which a portion of the adjustable toggle @il adapted to engage to limit the lower-most swing oi said toggle. Also engaged on the armr El is an upper stop screw a9 against which the upper portion of the toggle 34 is adapted to engage to limit the outward swing of said toggle.

For the purpose of ope-rating the toggle mechanism to actuate the gear segment tit and the pinion h5 to cause opening and closing of the crib discharge door, an air control mechanism is connected with the link pin 93 by means of a clevis W0 the forked end of winch is engaged on the pin $3' while; the opposite end is provided with a threaded recess in which the outer projecting end of an air operated piston rod lEiI is engaged. The piston rodv mi slidably pro-jects into one end of an air' cylinder 62 which is mounted in an inn clin-edfv position, as illustrated in Figure l, and is provided with a collar portion which is adapted to Contact a cylinder stop block w3 mounted on the exterior of the lower hopper 8L* to limit the downward swing of the air cylinder W2.

The lower end of the air cylinder IGZ is provided with a bottom or basev lli-ll including an eX- tensicn through which a pivot pin i435 projects. The pivot pin l' is supported on a bracket B06 which is securely bolted to a portion ofthe framework l of the mixer. Connected to communicate with the interior of the lower end of the cylinder 1'02 is one end of an elbow tting Illll to the other end oi which one end of an air hose w8 is connected. The air hose |03 is alsoconnected to,- the bottom end oia speed control valve IBS the upper end of which is connected to an elbow tting I III). Also connected to the elbow tting I I0 is one end oi an airA hose HI. The second end of the air hose i tI' is connected to an air control valve I I2. The elbow fitting l Iil is supported on the underside of an air pipe supporting bracket H3 which is rigidly bolted to a bracket arm Illl mounted on the exterior of the upper hopper 16.

The new of air into and out of the upper end of the air cylinder |02Y is through an elbow tting H5 to the outer end of which one end oi an air hose llt is connected. The second end of the air hose IIS is connected to the bottom of a speed control valve lli to the top of which one end of an elbow iitting H8 is connected. Connected to the second end oi the elbow fitting I I8 is one end4 of an air hose liti. The air hose M9 is also connected to the air control valve H2. The air control valve il-Z is provided with a control handle or lever liti which is adapted to be manually operated to actuate a four-way double passage Valve plug, oi a standard construction, within the control valve housing lli to permit air under pressure from an air pressure supply pipe I-.i to be admitted into either the air hose III` or the air hose il@ and at thesame time permit air pressure to be released from the other of said hose connections so that air may be admitted into the air cylinder it against one side oi the piston while the air on the opposite side of the piston is permitted to be exhausted. f

it will thus be noted that by operating the air control valve handle l@ that air may be admittcd into the air cylinder im on either side of the piston to cause operation of the piston rod and actuation of the toggle mechanism which governs the operation of the gear segment 36v which in turn rotates the pinion to either open or close the crib door 5%.

When the door control gear members and the toggle mechanism are in the positions illustrated in full lines in Figure l the crib door 5t is swung into the dotted line position illustrated in Figure 3' so that the door proper is moved completely out ofthe path ci discharge of the material from the crib to the lower hopper mi. Ii the air control handie 6291s now operated to admit air beneath the piston in the air cylinder HB2, the pis-` ton rod will be projected outwardly to actuate the toggle mechanisms causing the toggle 94 and the toggle links 92 to be moved beyond dead center thereby causing operation of the gear segment 5S and the pinion Q5 to move the door into a tightly sealed and locked position illustrated in full lines in Figure 3. When the toggle members Sil and Q2' are moved beyond dead center the toggle member 94 is adapted to engage against the upper stop 9S. With the toggle members 9A and 92 moved beyond dead center as described', the door 55 is positively locked in closed position and cannot be opened by any force applied to the door from the interior ofz the crib 2U. The door can only be opened by operating the air control handle |29 to again admit air above the piston in the cylinder* H32 to. pull the toggle mechanism back into the full line position illustrated in Fig ure. 1, thereby causing opening of the discharge door of the crib..

During the operation of the mixer it is essential, in some cases, to maintain the top of the upper hopper l@ tightly closed, particularly in the mixing and treatment of certain materials for the: moduction of chemical productsV such, for example, as .high explosive compounds requiring:

treatment in a tightly enclosed area obtainable in `the present mixer by the use of a material delivery hood and cover which is adapted to be iitted to the upper end of the crib 20. The bottom of the discharge hopper is adapted to be closed by means of a material receiving container adapted to be sealingly held in contact with the seal washer on the lower end of the discharge hopper 80.

In order to complete the confinement of the material being discharged from the mixer, the upper hopper 'i5 is provided with an inspection door 22 which is supported on the top of the upper hopper i6 by means of hinges 23 and a hinge shaft |24. To insure a tight t between the top of the upper hopper 'it and the bottom surface of the inspection door 122, a door seal |25 is provided in the top face of the upper hopper l against which the inspection door |22 is adapted to tightly seal. For the purpose of lockingT the inspection door |22 in sealing contact with the top of the upper hopper It, a locking mechanism is provided which consists of a pivot bolt |26 which is supported in a projecting lip i2? integrally formed to project outwardly from the upper outer portion of the upper hopper 16. Pivotally supported on the pivot bolt |26 above the lip E27 is a bell crank locking member consisting of a locking handle |28 and a shorter clamping arm or finger 29 positioned at an angle thereto and adapted to be moved into frictional locking contact with a friction block I3@ which is integrally formed or rigidly secured upon the top face of the marginal portion of the inspection door E22. The inspection door |22 not only provides an adequate closure and seal for the top of the upper hopper 16 but it also provides a means aiTordlng access to the interior of the hoppers 'it and 8u and to the crib door and hinge mechanisms to permit the same to be inspected and thoroughly cleaned after the treatment and discharge of products from the mixer.

With the parts assembled as described it will be seen that the machine may be set .in operation by starting the motor I5 after the air control handle |2l| has been operated to cause the crib door to be moved into the closed position illustrated in Figure 3. In one use of the mixer a material delivery hood may be moved into position to tightly seat upon the top flange 2| of the crib 2li to permit the diiferent ingredients to be mixed, to be deposited into the crib 20. When the motor -is started the 'mixing and mulling mechanisms within the crib are operated by the rotation oi the propulsion head 26. The inner and outer plow blades act to turn and move the ingredients alternately outwardly and inwardly into the path of the muller, so that the ingredients are thoroughly mixed and mulled to produce the desired products. During the treatment of the materials within the crib 2l) a cooling liquid is admitted into the jacket chamber 24 through the inlet nipple 51 and caused to circulate through the chamber 24 by means of the positioning of the radial baflles. The circulating liquid thus cools the wear plate 23 and is then discharged through the outlet nipple 60. The circulating liquid within the jacket chamber 24 thus acts to uniformly cool off the wear plate 23 and the materials which are being mixed and mulled thereon within the crib 20.

After the ingredients have been thoroughly mixed and mulled to produce the desired product, such as an explosive mixture requiring cooling during the mixing and treatment thereof, the

resultant product is ready to be discharged from the crib. Before the discharge of a treated batch of material, it is essential that the inspection door l22 be tightly locked in place and that a receiving container be sealingly pressed against the seal ring or washer 84 at the lower end of the lower discharge hopper 80. The crib door 66 is now opened, and this is accomplished by simply operating the air control handle to admit air under `pressure .into the upper end of the air cylinder m2 to force the piston downwardly in said cylinder thereby pulling the toggle mechanisms from the dotted line positions of Figure 1 to the full line positions to operate the door control gears and the door hinge shaft 'I3 to swing the door mechanism downwardly from the full line position of Figure 3 to the dotted line position so that the door tt is moved entirely out of the path oi discharge of the material permitting the material to drop downwardly through the lower hopper it@ and into the receiving container positioned against th-e bottom thereof. The receiving container may then be released from its engagement with the bottom of the lower hopper t@ and moved to any desired location.

In the mixing and treatment of materials for the production of high explosives it is desirable and important that the mixing and treating mechanisms as well as the door mechanisms be thoroughly cleaned after each cycle of operations. The plowing and mulling mechanism within the crib may be conveniently cleaned withthe removal of the material delivering hood from the top of the crib, and the door mechanisms may be cleaned by simply removing the hopper inspection door |22 after the locking handle |28 is pivoted to move the clamping nger |29 off of the door block |321 In the mixing and mulling of chemical mixtures for the production of products such as high explosives, it is essential that the crib door 66 is not only thoroughly sealed when closed but that it is also securely locked against opening, so that in case of an accidental explosion within the covered crib the explosive force will not open the door. This is made possible by the locked position of the toggle and gear control mechanisms of said `door which can only be released by the positive operation of the air control mechanisms.

Attention is called to the fact that the crib, the cooling jacket, the wear plate and the turret are all integrally formed or connected to produce a unitary structure which is adaptable for the mixing and treatment of materials in a temperature controlled area. While the crib jacket has been described as a medium whereby a cooling liquid may be circuitously circulated within the jacket beneath the wear plate to cool the plate and the materials being treated thereon, it is to be understood that a hot liquid may be circulated through the jacket to cause heating of the wear plate and the material being mixed thereon in case a product is being produced which requires an increase in temperature. The temperature control jacket may also be adapted for the use of the circulation of steam as a heating medium. It will also be understood that if cooling off of the materials being mixed in the crib is desired, that any other cooling medium may be circulated in the temperature control jacket in place of the circulation of cold water.

While the improved mixer is highly adaptable for the production of chemical mixtures, high explosives and other products requiring careful and expert handling in temperature controlled rea, it is to be understood that the mixer may also be conveniently adaptable for the reclaiming and reconditioning of foundry sand and the like.

It will, of course, be understood that various details of construction may be varied through a wide range without departing from the principles of this invention, and it is, therefore, not the purpose to limit the patent granted hereon otherwise than necessitated by the scope of the appended claims.

I claim as my invention:

1. In a muller including a crib having a muller element movable over the crib bottom, means for controlling the discharge of the crib contents comprising an opening in said bottom, a discharge hopper depending from the crib bottom and around said opening, a closure for said opening and movable in said hopper into tight engagement with the edge of the opening, and lever means in the hopper for supporting and moving said closure and being pivotally supported remote from said opening and to one side oi" said crib bottom so as to be clear of the discharge path of the crib contents when the same is being discharged from the crib, said lever means upon actuation to open said opening swinging said closure bodily to one side of the crib bottom and clear out of said discharge path so as to be remotely supported by the lever means independent ofA the crib bottom.

2, In a mulling apparatus a container defining a chamber for receiving material to be mulled 12 and having a side wall and a bottom wear plate, a turret carrying a rotatable mulling roll in said container frictionally engaging and pressing against said plate to comminute material between the plate and roll, a bottom wall for the container spaced from said wear plate and defining between it and said plate an area for receiving a heat exchange fluid, said turrent extending down through openings in said plate and bottom Wall and being integrally attached thereto, said side wall having its lower end resting on said bottom Wall and being secured thereto and said wear plate having its outer edge secured to said side wall.

AXEL G. GRANATH.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 428,134 Price May 20, 1890 885,781 Ord Apr. 28, 1908 1,337,333 Simpson Apr. 20, 1920 1,457,907 Heisler June 5, 1923 1,533,409 Hartshorn Apr. 14, 1925 1,812,559 Sampson June 3, 1930 1,926,083 Christensen Sept. 12, 1933 2,007,481 Staley July 9, 1935 2,239,029 Barrett Apr. 22, 1941 

